https://doi.org/10.1351/goldbook.09417
Extraction field around the sample that is pulsed to the working value for extracting ions for the time necessary for operation of a time-of-flight mass spectrometer, but is otherwise at a low value.
Note: This is the usual mode in time-of-flight secondary ion mass spectrometry systems, either for studying insulators, where charge neutralization is established while the extraction field is off, or for depth profiling using a second ion beam while the extraction field is off.